Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an endless belt-type
sensitive member assembly unit or "module", and more particularly
to one where an endless belt-type sensitive member is trained
in tension about a plurality of supporting rollers mounted
between the side frames of the unit.
In one aspect of the invention there is provided in a
belt-type photosensitive member unit for use in an electro-
photographic reproducing apparatus having a main body portion,
the unit normally being located in an operative position internal
to the main body and including a plurality of rollers rotatably
confined within a framework, a belt-type sensitive member being
trained about said plurality of rollers, and said rollers
comprising a drive roller, the improvement in said unit com-
prising: first guide means rigidly secured at two points along
the length thereof to the main body of the reproducing appaxatus;
second guide means attached to said sensitive member unit
outwardly thereof and adapted to cooperate telescopically with
said first guide means to permit,displacement of said sensitive
member unit to a position external to the main body.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 schematically shows the outline of the
sensitive member support means of a conventional unit;
Figure 2 schematically shows the outline of the
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sensitive member support means of the present invention;
Figure 3 is a perspective view showing the state of
the sensitive member unit after being withdrawn from the main
body of the reproducing apparatus;
Figure 4 is a cross-sectional view of the sensitive
member unit of Fig. 3; and
Figure 5 is a cross-sectional view showing the
sensitive member unit of Fig. 3 both at rest (solid lines) and
also when in the open position (dotted lines).
2. Discussion of the Prior Art
In a high speed electrophotographic reproducing appa-
ratus which has an endless belt-type photosensitive member and
in which an instantaneous exposure is effected by means of a
flash lamp, it is required to transport the photosensitive mem-
ber, i.e., the belt, in a flat or tensioned condition at the
moment of exposure, so that the image of an original document
may be projected onto the photosensitive member -- or "belt" as
it will be referred to hereafter -- in a satisfactory manner.
To this end, the unit in which the sensitive member or "belt" is
mounted is so constructed that part of the belt, i.e., at least
the portion thereof to be exposed to the light image, is usually
maintained flat. In addition, because the exposure is instan-
taneously effected by means of a flash lamp, the belt travels
continuously from the exposure station to the developing station,
transfer station, etc. without interruption of motion at every
exposure.
The belt on the sensitive member assembly unit or
"module", as it will be called hereinafter, should travel to the
successive stations of the above-mentioned series in a manner
that respective corresponding portions of the belt are positioned
properly at the related stations, and accordingly there should
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be provided a special belt-type sensitive member to meet this end
in connection with its usage.
Hitherto, a seamless endless belt-type sensitive mem-
ber has been used, generally being trained in tension about
supporting rollers mounted in the module, with at least the por-
tion thereof to be exposed to the light image being maintained in
a flat state, as mentioned above. The sensitive member of this
type is repeatedly used for reproducing an original document,
such that its service life is only about 5,000 to 10,000 repro-
duction cycles, resulting in the necessity to replace it frequently.Furthermore, for removing a sheet of copying paper stuck in the
reproducing apparatus, for removing stains such as toner residues
from the belt surface, or for removing dust adhering to the belt
surface, the module must be taken out from the main body of the
reproducing apparatus where it rests during operation. A sensi-
tive member to be set on the module is of an end~ess type, hence
for facilitating its replacement, all support must be provided
within the module, rather than outwardly of its periphery, so as
not to interfere with resetting of the endless belt into the unit.
As shown in Fig. 1, the construction of a known unit is, for
example, such that guide rails C along which a module A is with-
drawn from the main body of a reproducing apparatus, are provided
within module A, while rails B provided within the reproducing
apparatus extend into the interior of A in engaging relation to
the aforesaid guide rails C. The rails B are therefore necessarily
of a centilever type supported at only one point D by the repro-
ducing apparatus. For proper support of the heavy module A by the
cantilevered rails B, an extremely strong reinforcing member must
be provided at the point D where the load is concentrated. Be-
cause rails B are supported only at one end, i.e., at point D, therails B and C become deflected due to the weight of module A
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during the repeated cycles of withdrawal and reinsertion of module
A from and into, respectively, the reproducing apparatus. This
deflection results in inaccurate positioning of the exposure,
developing, transfer and cleaning stations relative to the belt
or sensitive member trained in tension around module A. Inaccurate
positioning adversely affects the reproducing function of the
apparatus itself, resulting in a poor quality image, such as a
defocused or an unevenly developed image.
SUMMARY OF THE INVENTION
The invention resides in an improved belt-type photo-
sensitive member unit for use in an electrophotographic repro-
ducing apparatus having a main body portion, the unit including a
plurality of rollers rotatably confined between a pair of side
frames, an endless belt-type sensitive member being trained about
the plurality of rollers for mounting, the rollers comprising a
drive roller and a roller provided with a member for adjusting the
tension of the endless belt-type sensitive member. The improve-
ment in the unit comprises two pairs of rails each rigidly sup-
ported at two points on support members provided within the main
body of the reproducing apparatus; two pairs of rails fixed to
the unit outwardly thereof and adapted to cooperate with the
first-mentioned pairs of rails to permit the unit to slide there-
along; reinforcing rails disposed between the first-mentioned
pairs of rails and the second-mentioned pairs of rails in a manner
to be slidable to a given position on the first-mentioned pairs of
rails, together with the sensitive member unit when same is with-
drawn from or returned into the interior of the reproducing appa-
ratus; and the unit being pivotally mounted on the second-mentioned
one of the pairs of rails such that the unit can be moved away
from the second-mentioned rails to provide an opening for access
to the endless belt.
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DESCRIPTION OF THE PREFERRED EMBODIMENT
To solve the previously-described problems, the present
invention generally provides a belt module comprising, see Fig. 2,
triple-section guide rails consisting of pairs of rails 5 and 6
rigidly supported at points 3 and 4 within the main body 1 of a
reproducing apparatus; two pairs of rails 7 and 8 provided out-
wardly of the periphery of belt module 2 and slidably fitted in or
engaged with the aforesaid pairs of rails 5 and 6 so as to mount
module 2 slidably with respect to the aforesaid rails 5 and 6; and
reinforcing rails (not visible in Fig. 2) inserted between the
first-mentioned pairs of rails 5 and 6 and the second-mentioned
pairs of rails 7 and 8. The aforesaid reinforcing rails are
adapted to be slid to a given position on the pairs of rails 5 and
6, following the movement of module 2 when this last is withdrawn
from main body 1 of the reproducing apparatus, such that the re-
inforcing rails may support the load of a heavy module 2 with the
load uniformly applied to the triple-section rail guides. Thus,
there is no risk that an excessive load would be exerted on a
single pair of rails alone. Module 2 is so constructed (see Fig.3)
that when in the position withdrawn out of main body 1 of the
reproducing apparatus, the module can be rotated about hinges
25,25' towards an operator (clockwise direction in Fig. 3) to
provide an opening between the unit itself and the support rails,
whereby the belt may be replaced with ease by releasing the roller
which holds it in tension. In the event that the surface of the
belt is stained due to adherence of toner or dust, or a sheet of
copy paper is stuck in the reproducing apparatus, then cleaning
of the belt surface or removal of the jammed copy paper from the
apparatus is possible with module 2 maintained in the position
withdrawn out of main body 1 of the reproducing apparatus.
According to the present invention, since module 2 is slidably
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supported on a pair of rails 5 and 6, each rigidly supported at
two points, all rails are free from deflection even after frequent
and repeated operations withdrawing and reinserting module 2 from
and into main body 1 of the reproducing apparatus. In addition,
the aforesaid rails supported at two points do not interfere with
replacement of a belt on module 2, such replacement being readily
accomplished.
A detailed description of the preferred embodiment of
the present invention will be given below in conjunction with
Figures 3 through 5.
Rail support members 9 provided within the main body 1
of a reproducing apparatus rigidly support two pairs of rails 10,
10' and 11, 11' mounted on main body 1 at points 3 and 4. The
two pairs of rails 10, 10' and 11, 11' are positioned (see Fig. 4)
in facing relation to another two pairs of rails 14, 14' and 15,
15' which are fixedly mounted on the outer wall of module 2, with
reinforcing rails 12 and a plurality of bearings 13 being inter-
posed between the respective rail pairs, the reinforcing rails 12
being slidable together with module 2. Thus, triple-section rail
guides in combination serve as a support for the unit. This is
done for the sake of distributing the load of the heavy module 2
uniformly among those rails.
In detail, when module 2 is withdrawn from main body 1
of the reproducing apparatus with the reinforcing rails 12 in-
serted between the pairs of rails 10, 10' and 11, 11' provided
on the main body 1 and the pairs of rails 14, 14' and 15, 15' of
module 2, the extremely heavy module 2 may be maintained out of
main body 1 for a long period of time, during which period clean-
ing of the belt surface or removal of a copy paper stuck in the
main body is effected, without risk of an excessive load being
inadvertently exerted on rails 10, 10' and 11, 11' and on the
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rails 14, 14' and 15, 15', since the reinforcing rails 12 inserted
in respective pairs of these rails serve to distribute the load
of the heavy module 2 so that it is shared by all the rails. When
module 2 is withdrawn from main body 1, the reinforcing rails 12
in turn are slid along the respective rails 10, 10' and 11, 11'
fixed on the main body and stop at a given position on those rails,
whereby the load of module 2 is shared among the pairs of rails
10, 10' and 11, 11', and the pairs of rails 14, 14' and 15, 15',
as stated above. When module 2 is pushed back into main body 1,
the reinforcing rails 12 are also slidingly returned on the
respective rails 10, 10' and 11, 11'.
Modular unit 2 is composed of a pair of opposing frames
16 and a plurality of rollers 17, 18, 19 and 20, one of which is
a driving roller. The aforesaid pairs of rails 14, 14' and 15,
15' are fixed to rail-attaching members 21 and 21' projecting
from the frames 16, thereby supporting the module 2 at rest, as
well as permitting it to travel back and forth on the rails 10,
10' and 11, 11' by way of the rails 14, 14' and 15, 15'. A belt
22 is trained in tension about the aforesaid plurality of rollers
17, 18, 19 and 20. An adjusting member 23, such as a jack screw,
is threaded radially into the shaft of roller 20 near the end of
the shaft. The adjusting member 23 is anchored with respect to
the directions of the double-headed arrow in Fig. 4 by means of
a screw-support member 24 attached to frame 16, for purposes of
providing the tension in belt 22. If adjusting member 23 is
turned to move shaft 20 toward the screw-support member 24 (i.e.,
the leftward direction of the arrow in Fig. 4), then belt 22 will
be demountable from module 2. Although in this embodiment a
screw is provided for purposes of replacing a used belt by a new
one or for tensioning the belt, the adjusting means are not
limited to a screw since spring tension may be utilized for
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tightening or for permitting replacement of belt 22. Modular unit
2, as set forth, is adapted to be pivotally moved in a manner to
provide an opening between the unit itself and the pairs of rails
14, 14' and 15, 15', after withdrawal from main body 1. In this
embodiment, module 2 is coupled to main body 1 by hinges 25 and
25' between the rail mounts 21, 21' and the unit frame 16.
For retaining or locking module 2 in the position pro-
viding an opening between it and the rails 14, 14' and 15, 15' for
a long period of time during which replacement of belt 22 trained
about the plurality of rollers can be effected, there is provided
between rail mounts 21, 21' and unit frame 16, a mechanism for
locking module 2 in open position. As shown in Figs. 3 through 5,
an arm 28 is pivotally mounted between brackets 26 and 26', which
have an L-shape in cross section and are rigidly fastened to unit
frame 16. Arm 28 has a pin-engaging cut-away portion 27 near its
free end and is normally urged towards frame 16, i.e., in the
clockwise direction in Fig. 3. A pin 30 is mounted on a pin
support member 31 which in turn is affixed to one end of rail
mount 21, so as to fit in the pin-engaging cut-away portion 27 of
the above-mentioned arm. Pin 30 and arm 28 are located in spaced
relation to each other in a manner to provide a given opening for
module 2 with respect to the rails 14, 14' and 15, 15' when the
pin and arm are engaged. Fig. 5 illustrates the pivotal movement
of modular unit 2 with respect to main body 1. If module 2 is
moved from rest in a direction to create an opening between same
and the rails 14, 14' and 15, 15', as shown in Fig. 5, the free
end of arm 28 will come to bear on pin 30 against the action of
a spring 29. When cut-away portion 27 of arm 28 comes into
engagement with pin 30, module 2 will be locked in a position to
provide an opening between same and rails 14, 14' and 15, 15'.
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A shaft 32 passing through module 2 in the transverse
direction thereof (see Fig. 5) is held by the frames 16 and has
one end which engages the lower face of arm 28 in a manner to
normally urge the arm upwardly. Shaft 32 is urged in the leftward
direction in Fig. 5 under the action of a coil spring 33. If
shaft 32 is manually urged in the direction of the arrow shown
adjacent the open -- i.e., dotted line -- position in Fig. 5, arm
28 is raised up, thereby releasing module 2 from locked position.
The modular unit 2 thus constructed and having the belt
22 trained in tension therearound is actuatable by the driving
roller when the unit is returned into main body 1, so as to per-
mit effecting reproduction of an original image. When there
arises the necessity of cleaning belt 22, removing a copy paper
stuck in main body 1 or replacing a belt 22, actuation of module
2 is stopped and it is then withdrawn from main body 1 towards an
operator (in the leftward direction in Fig. 3), whereby a copy
paper stuck in main body 1 can be removed or cleaning the surface
of belt 22 accomplished by rotating the belt by means of a manual
drive wheel (not shown), module 2 meanwhile being maintained in
the withdrawn position. For replacing a used belt 22 by a new one,
modular unit 2 is withdrawn from main body 1 and urged in the
clockwise direction (Fig. 3) about the hinges 25 and 25', to
thereby provide a wide opening between the unit and rails 14, 14'
and 15, 15'. After arm 28 mounted on unit 2 has been locked by
pin 30, the screw 23 passing through the end of roller shaft 20
(as shown in Fig. 4) is manipulated to move the shaft in the left-
ward direction of the arrow in Fig. 4, thereby relieving tension
on belt 22, whereby the used belt 22 can be taken away from the
unit and replaced by a new one. At completion of belt replacement,
screw 23 is manipulated in the counter-direction to exert tension
on the fresh belt 22. For reinserting module 2 in main body 1,
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shaft 32 shown in Fig. 5 is manually urged rightward against the
force of spring 33 so as to release arm 28 from engagement with
pin 30. Then, module 2, while resting on rails 14, 14' and 15,
15', is manually urged toward main body 1, thereby being returned
to its home position.
According to the present invention, there are provided
triple-section rail guides in combination, which consist of pairs
of rails 10, 10' and 11, 11' fixed on support members 9 at points
3 and 4 provided within main body 1, reinforcing rails 12 and
pairs of rails 14, 14' and 15, 15' mounted on the outer wall of
module 2. The latter pairs of rails are in facing relation to
the former pairs of rails by way of the reinforcing rails 12. In
particular, when module 2 is withdrawn from main body 1 and
allowed to stand on the extended rails for a long period of time,
the load of the extremely heavy modular unit 2 is distributed by
the reinforcing members so as to be uniformly applied to respec-
tive rails of the triple-section rail guides, without concentra-
tion of such a heavy load on one pair of rails only. Thus, the
respective rails are maintained free from the deflection
experienced with the conventional rails supported at one side,
without provision of a particularly strong reinforcing member for
supporting such rails. Furthermore, since module 2 is pivotally
movable on the rails 14, 14' and 15, lS' to afford selective
opening between same and main body 1, these pairs of rails on
unit 2 do not interfere with replacement of a belt 22.
